This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
This is a most valuable free-flowering plant, producing its beautiful white flowers in great profusion the whole year through. It is a most useful plant for florists, etc, who have a demand for white flowers for making wreaths, etc, although some dislike the shape of the flower, and find fault with the yellow centre for such a purpose; but this can be partly remedied by carefully replacing the petals with the finger and thumb, or giving them a gentle blow with the mouth, and then cutting out the yellow centre with a pair of sharp scissors. This alters the look of the flower entirely.
To have it in flower the whole year through, it is better to have two sets of plants; and June is a good time to strike a few cuttings to be grown on for winter blooming. Take the growing points and dress them in the usual way, and insert them in the propagating-pit or in pots, and plunge them in a gentle hotbed, watering them with tepid water, and shading them from bright sun until they are rooted, when they should be potted off singly into 3 and 4 inch pots in light loamy soil, with a little thoroughly-decayed cow-dung, sand, and charcoal-dust, well mixed together. When potting, give them a firm hold of the soil, and water them gently with tepid water; after which plunge them in a warm pit, and keep close and shaded for a few days till they take a hold of the new soil. When they have filled these pots with roots, shift them into 5 or 6 inch ones, using the same compost in a rougher state, after which they will grow away vigorously, and require to be pinched and have the growths nicely regulated, and occasionally syringed overhead on fine days after noon, to keep up a moist growing atmosphere.
The next shift will be into 8 or 9 inch pots, which is quite large enough to flower them in during the winter; and they produce their flowers in great abundance when a little pot-bound, and gently stimulated with manure-water. The points must not be pinched too late in the autumn. They will throw out abundance of flowers at the axils of the leaves if grown in a light airy position, and have a temperature ranging from 50° to 55°. They will luxuriate in a Melon-house along with Primulas, and should be treated much the same, or in a warm greenhouse near the glass.
We have it thriving admirably planted out on the back wall of a vinery, where it is not too much shaded, and the quantity of flowers it produces in such a position is something marvellous.
The plants must be liberally supplied with liquid manure when making their growth, and occasionally throughout the winter months. It also "tells " well as an exhibition flowering-plant when grown on to a large size, the white flower in great profusion on a large well-trained specimen being almost unique. Some of the best-shaped plants which have flowered during the winter should be selected for this purpose, and partially shaken out, repotted, and cut back, and placed in a gentle heat, and grown on to any size which may suit the cultivator's taste and convenience. Dundonian.